Sealant and coating compositions desirably have a combination of properties which render them particularly suitable for their intended applications. Such compositions should be able to be packaged in sealed containers or cartridges and stored for relatively long periods of time without objectionable "setting up" or hardening, that is curing of the components in the package. The one component sealant composition should form a relatively tack-free surface upon application and upon exposure to atmospheric moisture should cure without the formation of bubbles within a suitable time. The two component system can be formulated into package stable systems with adjustable cure rate and cured sealant properties. When cured, they should adhere tenaciously to a wide variety of surfaces such as glass, aluminum, concrete, marble, and steel. They should also have sufficient elasticity and flexibility to withstand contraction and expansion of panels, and the like, generally associated with temperature variations as a result of climatic changes and/or wind forces.
U.S. Pat. No. 3,634,306 to Schroeder relates to a moisture curing free isocyanate containing polyurethane polymers made from a polyol component containing a branched chain polyoxybutylene polyol in order that a paraffinic or alicyclic hydrocarbon-containing solvent can be employed and still obtain essentially clear solutions. The amount of the polyoxybutylene polyol component utilized is at least 25 mole percent and preferably at least 40 mole percent. The molecular weight of the polyoxybutylene polyol is low, that is, 5,000 or less and preferably 3,000 or less.